<div id="loginLayout">
    <div class="container login">
        <div class="loginTabs">
            <?php
            if(empty($_SESSION['username'])){
                echo '您尚未登录';
            }else{
                echo '已登录，您的用户名：'.$_SESSION['username'] ;
            }

            ?>
            <div>
                <button id="login">登录</button>
                <button id="logout">注销</button>
            </div>
        </div>
    </div>
</div>